Connection timed out for Adyen PSP webhooks

Hopefully posting in the right place, not 100% friend with Discord UI/UX. ::) A client is receiving timeouts (without explicit 5xx-errors but I assume it's 502/522, if I try the same in the browser it shows as that). Not sure why we're receiving them and tried searching for others having issues with Adyen since it's only their requests that seem to get this error. The request works if CF is set to only pass the traffic on to AWS (which hosts the site) but timeouts when it's proxied through CF. Any quick tips on what could be the issue or where to start digging deeper into this issue? The timeouts don't show up in Cloudflare analytics as 502 or 522 at least, I can trigger them as 405 if I run a get against the url (it expects post requests), so it does trigger in the CF logs if I do an incorrect request on purpose.